Question

I have some slow linq queries and need to optimize them. I have read about compiled queries and setting the merge option in NoTracking in my readonly operations.
But I think my problem is that I have too many Includes so the number of joins done in the DB is huge.

context.ExampleEntity
      .Include("A")
      .Include("B")
      .Include("D.E.F")
      .Include("G.H")
      .Include("I.J")
      .Include("K.M")
      .Include("K.N")
      .Include("O.P")
      .Include("Q.R")
      .Where(a => condition1 || complexCondition2)

My doubt is, if I put the Where before the Includes, would this filter ExampleEntity objects before making all the joins?? Im not sure about how linq queries are translated to SQL

Answer 1

“Yes”.
Each sub-query passes it’s results to the next. Moving the Where first will filter, then perform the includes against a potentially smaller set.

Whether that makes sense in the context of your specific query is up to you to decide.